HOUSTON - A university building under construction collapsed in the US state of Texas on Saturday, leaving four workers injured -- one critically, according to local media reports.

The incident occurred before 11:00 am at the Texas A&M University in College Station, a central Texas city about 150 km north of Houston, local TV KTRK reported. The building was part of a new Equine Center under construction.

All four victims have been sent to hospitals, with a 35-year- old male in critical condition. Some 25 to 30 workers were reported to be at the site when the collapse happened, and all of them have been accounted for.

TV footage showed twisted metal beams at the site, where ground was broken last October. The 80-million-dollar facility, when completed, will provide a home for equine science education, research and outreach initiatives dedicated to the welfare of horses, a university press release said.

Brian Blake with the Engineering Extension Service for Texas A& M, an eyewitness, told the local media that the facility was under construction on university property, but not directly on campus. Earlier he said that there were "numerous injuries."

Local police are trying to determine what caused the collapse. They have identified the contractor as Gamma Construction Company, which has offices in Houston and San Antonio. The company cannot be immediately reached for comments.

Texas A&M is the seventh-largest university in the United States and the largest in Texas. The university is home to more than 50,000 students, according to information on its official website.